SPECIAL FEATURES

Engine Management

The Sense of Going Full Throttle

With a diverse range of throttle position sensors and throttle bodies, CAMBIARE shares some insight on this integral range.

The throttle body is integral to combustion engines and controls the amount of air that is let into the engine during varying operating conditions. Controlled by the movement of the accelerator pedal, the butterfly valve in the throttle body was traditionally operated mechanically by means of a cable. The harder the pedal was pushed, the wider the throttle valve opens.

The ‘drive-by-wire’ system found in engines today have a throttle position sensor which maintains the relationship between the driver’s control of the accelerator pedal and the throttle body. The throttle position sensor is used to monitor the position of the butterfly valve to ensure that the throttle body actuator works in conjunction with the accelerator pedal.

A SYMBIOTIC RELATIONSHIP

The throttle position sensor continually measures the position of the throttle butterfly and is combined with other data such as air temperature, engine RPM, mass airflow and the speed of throttle position changes which are monitored by the ECU. This information precisely determines how much fuel is needed to be injected into the engine at any given moment. A working throttle position sensor creates a symbiotic relationship between the driver and the throttle body, allowing the vehicle to accelerate, cruise or decelerate smoothly and efficiently.

Given the working relationship between the throttle body and the throttle position sensor, a fault in either part can cause similar symptoms to manifest. Common issues caused by a failing throttle body and/or throttle position sensor include:

Car will not accelerate, lacks power when accelerating, or accelerates on its own

Engine will not idle smoothly, idles too slowly, or stalls

Car accelerates but will not exceed a relatively low speed or shift up

The ‘check engine light’ illuminates, accompanied by any of the above behaviour

THE RIGHT COURSE OF ACTION

Due to the similarities of the symptoms shared between a problematic throttle body and throttle position sensor, it is imperative that technicians inspect the system thoroughly to ensure that they find the root of the problem.

Detecting failures in throttle bodies

Lack of maintenance is one of the key causes of any system failure. This is often due to accumulated contamination. The carbon particles and oil mist in the vapour from the crankcase ventilation system of the engine causes a build-up of carbon deposits within the throttle body. This restricts the airflow and in extreme cases, may cause the valve to stick so that adequate air cannot reach the engine.

Detecting failures in the throttle position sensors

A failing throttle position sensor will hinder engine performance because the air-to-fuel ratio will be compromised and it can fail in several ways. All of which can result in poor fuel economy and performance limitations. The sensor can fail gradually, or all at once. When this happens, the ‘check engine light’ will likely be illuminated and in the case of most modern vehicles, it will operate in “limp home” mode of operation with reduced power if a failure is detected. This is intended to allow the driver to safely get off a busy road when there is a problem with the throttle position sensor.

Replacement upon failure

Throttle bodies and throttle position sensors are non-serviceable items. This means that when there is any evidence of failure, they need to be replaced. It should be noted that the failure of these components are not always easily diagnosed. The only way to ensure the correct diagnosis is by carefully analysing the fault codes via live data readings and visually inspecting the part.

QUALITY HELP ASSURED

With one of the most comprehensive ranges of vehicle electronics and engine management parts in the UK, Cambiare recognises the need for aftersales support and technical expertise to match it. This is why; Cambiare’s specialist team maintains vigilance over aftermarket demands and developments to ensure that they do not skip a beat ensuring that the UK aftermarket is getting what they need, when they need it.

Cambiare’s technical hotline (0845 543 8280) provides customers with the guidance they need on anything from navigating through the catalogue for parts, to the nitty-gritty technical questions. Whether it is to help customers identify the right part for the application, cross-referencing, fitment enquiries, or to troubleshoot and diagnose an automotive problem, the technical team has a wide range of expertise to cater for their diverse hotline enquiries.